Image projecting device and method

ABSTRACT

An image projecting device and method are presented. The device comprises a light source system operable to produce a light beam to impinge onto an active surface of a spatial light modulator (SLM) unit formed by an SLM pixel arrangement; and a magnification optics accommodated at the output side of the SLM unit. The light beam impinging onto the SLM pixel arrangement has a predetermined cross section corresponding to the size of said active surface. The SLM unit comprises first and second lens&#39; arrays at opposite sides of the pixel arrangement, such that each lens in the first array and a respective opposite lens in the second array are associated with a corresponding one of the SLM pixels

FIELD OF THE INVENTION

[0001] This invention relates to a compact-size image projecting deviceand method.

BACKGROUND OF THE INVENTION

[0002] Microdisplays are miniaturized displays, typically with a screensize of less than 1.5″ diagonal. Microdisplays are commonly used in dataprojectors, head mounted displays, and in the traditional viewfinders ofdigital cameras. Microdisplays can be implemented within compactprojectors, in viewfinders of handheld Internet appliances and in mobilephones for Web surfing and videoconferences, because full computerscreens can be viewed.

[0003] Most microdisplays use a light-valve made of a silicon chip asthe substrate material. The chip also houses the addressing electronics(at least an active matrix with integrated drivers), usually implementedin standard CMOS technology which allows very reliable and stablecircuits, as well as very small pixel pitches (down to 10 μm or evensomewhat smaller), as well as high display resolutions.

[0004] There are known reflective and transmissive light valves.Reflective light valves bounce light off the displayed image into theviewer's lens or the projection lens. Transmissive light valves aresimilar to backlit, portable computer screens using LCD (Liquid CrystalDisplay) and EL (electro-lumination) technologies. Common reflectivelight valves are based on Liquid Crystal On Silicon (LCOS) and tiltedmicro-mirrors (DMD). Common transmissive light valves are based onActive-Matrix Liquid Crystal Displays (AMLCD).

[0005] Projectors that use transmitting microdisplays as mentioned abovetypically comprise an optical path that includes a light source and aSpatial Light Modulator (SLM), in which a beam shaping optic componentas well as a polarizing component are disposed between them. Anotherpolarizing component and a magnifying optic component are generallydisposed between the SLM and the projection surface. The SLM is coupledto a video processing driver to produce the image modulation of thelight according to an input signal.

[0006] Common optical difficulties in the design of known projectorsbased on microdisplay are: low energy efficiency; low brightness andnon-uniformity of the output image due to the source non-uniformintensity distribution (i.e. Gaussian distribution over the SLM surface)and intensity losses; low focus depth of the output image. In laserbased projectors, the “speckle” phenomena of a Laser source according towhich, a granular pattern of light pervade the image, is also atechnical difficulty. Other common difficulties directly related to theoptical difficulties and to the hardware implementation are: size,weight, optical complexity, power consumption and the mobility of theoverall projecting device.

[0007] Different methods and devices addressed to overcome one or moreof the above-mentioned difficulties are disclosed by the following.

[0008] U.S. Pat. No. 5,971,545 discloses a compact and energy efficientprojection display utilizing a reflective light valve. The output beamsof the light sources are received by at least one spatial lightmodulator. The modulated output beams are collimated and combined. Aprojection lens receives the collimated and combined output beams anddirects them towards a projection screen. Energy efficiency is achievedby using sequentially strobed RGB light sources instead of a white lightsource.

[0009] U.S. Pat. No. 5,777,789 discloses an optical system forhigh-resolution projection display, consisting of reflectionbirefringent (double refractive) light valves. The LCD projectorcomprises a polarizing beam splitter, color image combining prisms,illumination system, projection lens, filters for color and contrastcontrol, and a screen. The illumination system includes a light sourcesuch as a metal-halide arc lamp, an ultraviolet and infrared filter orfilters positioned in the optical path from the light source forfiltering out the infrared and ultraviolet light emitted from the lightsource, a light tunnel for providing uniform light intensity, and arelay lens system for magnifying the illumination system output planeand imaging said plane onto the liquid crystal light valves.

[0010] U.S. Pat. No. 5,975,703 discloses an image projection devicehaving an SLM and a polarized source system. The optical system usespolarized light manipulated by at least one of a conicoid, or planeoptical elements to effect a folded mirror system to project an imageonto a screen by utilizing input light components of more than one stateof polarization, thus reducing intensity losses over the optical systemdue to polarization filtering. The system supplies light components ofsubstantially orthogonal polarizations for separate areas of the SLM tobe output onto a projection screen.

[0011] U.S. Pat. No. 6,183,092 discloses a laser projector whichincludes a laser apparatus and a reflective liquid-crystal light valvecapable of speckle suppression through beam-path displacement bydeflecting the beam during projection, thereby avoiding both absorptionand diffusion of the beam while preserving pseudocollimation(noncrossing rays). The latter, in turn, is important to infinitesharpness. Path displacement is achieved by scanning the beam on thelight valves which also provides several enhancements—in energyefficiency, brightness, contrast, beam uniformity (by suppressing bothlaser-mode ripple and artifacts), and convenient beam-turning totransfer the beam between apparatus tiers. The deflection effect isperformed by a mirror mounted on a galvanometer or motor for rotaryoscillation; images are written incrementally on successive portions ofthe light valve control stage (either optical or electronic) while thelaser “reading beam” is synchronized on the output stage. The beam isshaped, with very little energy loss to masking, into a shallowcross-section which is shifted on the viewing screen as well as thelight valves. Beam-splitter/analyzer cubes are preferred over polarizingsheets. Spatial modulation provided by a light valve and maintained bypseudocollimation enables imaging on irregular projection media.

[0012] U.S. Pat. No. 5,517,263 discloses a compact size projectionsystem which includes a bright light source of polarized light, and aspatial light modulator, having an alignment layer, to modulate thepolarized projection light, wherein the bright polarized light source isaligned with the alignment layer to permit the polarized light to passtherethrough without the need for unwanted light blocking polarizers.The use of a polarized laser source together with its proper alignmentwith the light valve, enables substantially all of the laser light beamsto be utilized by the SLM to form the projected image. Without the useof filters and/or polarizers with the light valve, the intensity lossesof the laser optical output are thus reduced. Furthermore, the lightemanating from a laser is polarized, and thus, there is no need forpolarizing filters, which would otherwise reduce the laser light energy.

[0013] U.S. Pat. No. 5,704,700 discloses a laser illuminated andSLM-based projection system that includes a microlaser array coupledwith a beam shaper to produce a bright (i.e. having a uniform intensitydistribution) projection light beam to be impinged over the SLM. Thebeam shaper includes a binary phase plate, a microlens array arrangementor a diffuser arrangement to modify the shape and intensity profile ofthe projection light beam. The laser light illuminating the light valvethus has a uniform intensity distribution for projecting an extremelybright image, and is confined substantially to the pixel portion of thelight valve.

SUMMARY OF THE INVENTION

[0014] There is a need in the art to facilitate projecting of images byproviding a novel miniature projector device and method.

[0015] The device of the present invention is lightweight and highlyefficient, and is capable of utilizing a high-ratio polarized lightsource, high-efficiency SLM performing digital processing of data to beimaged so as to significantly reduce the speckles' associated effects,as well as performing digital processing of a projected image to improveits uniformity.

[0016] According to one broad aspect of the present invention, there isprovided an image projecting device comprising a light source systemoperable to produce an incident light beam of a predetermined crosssection to be incident onto the active surface of a spatial lightmodulator (SLM) unit formed by an SLM pixel arrangement, saidpredetermined cross section of the incident beam corresponding to thesize of said active surface; and a magnification optics accommodated atthe output side of the SLM unit; the device being characterized in thatsaid SLM unit comprises first and second lens arrays at opposite sidesof the SLM pixel arrangement, such that each lens in the first array anda respective opposite lens in the second array are associated with acorresponding one of the SLM pixels.

[0017] The device of the present invention may utilize a transmissiveSLM type that does not require polarization of the light, oralternatively may utilize an SLM of the kind operating with specificallypolarized light. In the latter case, the device is designed so as toprovide specific polarization of the SLM input and output light. Thiscan be implemented by using a polarizer unit at the output of the SLMand either using an input polarizer or a light source of the kindgenerating high-ratio polarized light. The input polarizer may be partof the light source system or of the SLM unit.

[0018] The light source system may comprise an optical arrangementoperable to provide substantially uniform intensity distribution withinthe cross-section of the incident light beam. This optical arrangementincludes a diffractive element (commonly referred to as “top-hat”)operable to modify the beam intensity distribution to produce thesubstantially uniform intensity distribution of the beam within itscross-section.

[0019] Preferably, if the use of polarized light is required, the lightsource used in the device of the present invention is of the kindgenerating a high-ratio polarized light beam (thereby eliminating theuse of a polarizer at the input side of the SLM unit), and preferablyalso of the kind generating the light beam of the cross sectionsubstantially of the size of the active surface of the SLM unit (thusenabling the elimination of the beam shaping optics) or alternativelyequipped with a beam shaping optics to provide the desired beam crosssection.

[0020] According to another broad aspect of the present invention, thereis provided an image projecting device comprising a light source systemoperable to produce a light beam to impinge onto an active surface of aspatial light modulator (SLM) unit formed by an SLM pixel arrangement,said incident light beam being linearly polarized, having apredetermined cross section corresponding to the size of said activesurface; and a polarizer unit and a magnification optics accommodated atthe output side of the SLM with respect to the direction of lightpropagation through the device, the device being characterized in that:

[0021] said light source system comprises a light source generating saidlinearly polarized light beam having the cross section substantiallyequal to the size of the active area of the SLM unit; and

[0022] said SLM unit comprises first and second lens' arrays at oppositesides of an SLM pixel arrangement, such that each lens in the firstarray and a respective opposite lens in the second array are associatedwith a corresponding one of the SLM pixels.

[0023] Preferably, the above device also comprises a diffractive opticsaccommodated in the path of light propagating towards the SLM unit toprovide substantially uniform intensity distribution of the incidentlight beam within said cross section.

[0024] Preferably, the device of the present invention comprises animage processor system (control unit) operable to carry out at least oneof the following: applying digital processing to data indicative of animage to be projected so as to avoid or at least significantly reducethe speckle-associated effects in the projected image; processing ofdata indicative of the projected image to correct for non-uniformitiesin the light intensity; and analyzing data indicative of theenvironmental condition to adjust the intensity and/or the color mixtureof the incident light beam.

[0025] Thus according to yet another aspect of the present invention,there is provided an image projecting device comprising a light sourcesystem operable to produce a light beam to impinge onto a active surfaceof a spatial light modulator (SLM) unit formed by an SLM pixelarrangement, said incident light beam being linearly polarized andhaving a predetermined cross section corresponding to the size of saidactive surface, and a polarizer unit and a magnification opticsaccommodated at the output side of the SLM with respect to the directionof light propagation through the device, the device being characterizedin that it comprises an image processor system operable to carry out atleast one of the following: (i) applying digital processing to dataindicative of an image to be projected so as to reduce effectsassociated with creation of speckles in the projected image; (ii)processing of data indicative of the projected image to correct fornon-uniformities in the light intensity; and (iii) analyzing dataindicative of an environmental condition to adjust at least one of theintensity and color mixture of the incident light beam.

[0026] The device of the present invention may be operable to providecolor images. This can be implemented by utilizing three separate SLMpixels each for at corresponding one of three primary colors, or byutilizing the same SLM pixels for all the primary colors, but providingtime modulation of the color light components. The analysis of the dataindicative of the environmental condition may alternatively oradditionally be aimed at adjusting the color mixture of the incidentlight beam.

[0027] The device of the present invention can be used with anyconventional video generating device to project images onto an externalscreen surface. The device can be operable to project the same imagewith two different angles of projection, thereby enabling observation ofthe same image by two different observers, and also allows for privateoperation of the respective one of the images by each of the observersthrough his viewing area.

[0028] The technique of the present invention allows for combiningimages projected by several micro-projectors of the present invention,thereby allowing the creation of a large combined image; projecting theimage onto a concaved screen surface; and creation of stereoscopicimages by using two micro-projectors or the single micro-projectorequipped with a rotating mirror.

[0029] The present invention, according to its yet another aspectprovides a method for projecting an image comprising:

[0030] (a) creating an incident light beam having a predetermined crosssection corresponding to a size of an active surface of a spatial lightmodulator (SLM) unit formed by an SLM pixel arrangement and directingsaid incident light beam towards said active surface;

[0031] (b) passing said light through the SLM unit having first andsecond lens' arrays at opposite sides of the SLM pixel arrangement, eachlens in the first array and a respective opposite lens in the secondarray being associated with a corresponding one of the SLM pixels,concurrently operating the SLM pixel arrangement with an imaging signalrepresentative of an image to be projected;

[0032] (c) passing modulated light emerging from the SLM unit through amagnifying optics to be projected into a projecting surface.

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to understand the invention and to see how it may becarried out in practice, preferred embodiments will now be described, byway of non-limiting example only, with reference to the accompanyingdrawings, in which:

[0034]FIG. 1 is a schematic block diagram of a projecting deviceaccording to the invention showing the main optical components a lightpropagation scheme;

[0035]FIG. 2 more specifically illustrates the operation of adiffracting element (top-hat) used in the device of FIG. 1;

[0036]FIG. 3A illustrates the front view of the windowed structure of anSLM used in the device of FIG. 1;

[0037]FIG. 3B illustrates the structure of a lenslet array used with theSLM of FIG. 3A;

[0038]FIGS. 4A and 4B show beam propagation schemes through,respectively, the SLM of FIG. 3A and the SLM-with-lenslet array of FIG.3B;

[0039]FIG. 4C illustrates a specific example of the SLM unitconstruction;

[0040]FIGS. 5A and 5B demonstrate the principles of intensity lossescaused by using unpolarized and polarized light sources, respectively;

[0041]FIG. 6 more specifically illustrates an image processor unitaccording to the invention used with the device of FIG. 1 to improve thequality of the projected image;

[0042]FIGS. 7A and 7B more specifically illustrate the operation of thedevice of FIG. 6 to improve the brightness within the projected image;

[0043]FIGS. 8A and 8B more specifically illustrate the operation of thedevice of FIG. 6 aimed at solving the speckles-associated problem;

[0044]FIG. 9 is a flow diagram of the main operational steps in a methodaccording to the invention aimed at color-mixture modulation of lightinputting the SLM;

[0045]FIGS. 10A to 10E schematically illustrate different examples ofthe implementation of projection of color images suitable to be used inthe device of the present invention; and

[0046]FIGS. 11A to 11H schematically illustrate different applicationsof the projecting device according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0047]FIG. 1 is a schematic block diagram of a projecting device 1according to the invention showing the optical components of a lightpropagation scheme. The device 1 comprises a light source system LSSincluding a light source 2 generating a collimated light beam 4, anoptical arrangement including a diffractive element 34 (“top-hat”)operable to affect the intensity distribution of the beam 4 to producesubstantially uniform intensity distribution of the beam 4 within itscross section, and a beam shaping optics (beam expander) 6 that affectsthe cross section of the beam 4 to be substantially equal to the size ofan active surface defined by a pixel arrangement 5 (the so-called“windowed structure”) of an SLM unit 12 (such as the liquid crystalbased SLM Module RS170 commercially available from Kopin Corporation,USA).

[0048] It should be noted that the provision of the beam expander 6 isoptional, and the same effect can be achieved by providing anappropriate light source, for example, a laser diode/DPSS laser modulewith a beam diameter of 6 mm to cover the image modulation area on theSLM.

[0049] It should also be noted that the SLM unit may be of the kingoperating with randomly polarized light. Alternatively, the SLM unit maybe of the kind operating with specifically polarized light. In thiscase, the light beam impinging onto the SLM pixel arrangement has aspecific linear polarization, and the device comprises an outputpolarizer (analyzer) 18 shown in dashed lines since its provision isoptional depending on the kind of SLM used in the device. The polarizer18 has a preferred orientation of the plane of polarization eithersimilar to that of the incident light beam 4 or 90°-rotated, andtherefore blocks either the part of light that has been rotated by theSLM, or the part that has not been affected by the SLM. As for thepolarization of the incident light beam, it is preferably achieved byusing the light source of the kind generating high-ratio polarizedlight, but can, generally, be achieved by using a light sourcegenerating a randomly polarized light and using a separate polarizer(not shown) at the input side of the active surface 5. This inputpolarizer can be a part of the light source system, a part of the SLMunit, or can be a stand-alone unit accommodated between the light sourceand the SLM unit.

[0050] Thus, in the example of FIG. 1, the SLM is of the kind operatingwith polarized light, the light source generates high polarization ratiolight, and the output polarizer is used. The term “high polarizationratio” is typically referred to as that of about 1:50, 1:100 polarizedlight or above, and can for example be achieved with a laser diode andDPSS laser modules, such as the GMC-532-XF5 laser module seriescommercially available from Lasemate Corporation USA.

[0051] The construction of the SLM pixel arrangement 5 is known in theart and therefore need not be specifically described except to note thatit comprises a two-dimensional array of active cells (e.g., liquidcrystal cells) each serving as a pixel of the image and being separatelyoperated by a modulation driver 11 to be ON or OFF and to perform thepolarization rotation of light impinging thereon, thereby enabling toprovide a corresponding gray level of the pixel. Some of the cells arecontrolled to let the light pass therethrough without a change inpolarization, while others are controlled to rotate the polarization oflight by certain angles, according to the input signal from the driver11.

[0052] The SLM unit 12 further comprises a first lenslet array 10 at theinput side of the pixel arrangement and a second lenslet array 14 at theoutput side of the pixel arrangement. Practically, the lenslet arrayscan be integral with the pixel arrangement being mounted onto theopposite surfaces thereof. The construction and operation of the SLMunit with lenslet arrays will be described more specifically furtherbelow with reference to FIGS. 3A-3B and 4A-4C. The lenslet array is atwo-dimensional array of miniature lenses that matches the array ofactive cells of the SLM, such that each lens from the array 10 and therespective opposite lens from the array 14 are associated with thecorresponding one of the active cells. The lenslet array 10 thusclusters the light beam 8 to correspond to the image modulation areawithin the active surface 5 of the SLM elements by splitting the lightbeam impinging thereon into a plurality of components and focusing eachcomponent by the respective lenslet to the respective pixel (i.e. eachlenslet corresponds to a single pixel), thus improving the lightefficiency of the process.

[0053] Thus, the incident light beam (e.g., linearly polarized lightbeam) of the substantially uniform intensity distribution 4 is expandedresulting in a beam 8 with the cross section substantially equal to thesize of the active surface of the SLM. The beam 8 passes through thelenslet array 10 resulting in the clustered light that passes throughthe SLM pixel arrangement and is modulated in accordance with the imageto be projected. The modulated light emerging from the SLM is collectedby the second lenslet array 14, that cancels the clustering effect ofthe first lenslet array 10, thus producing a beam 16 having a uniformcross section as that of the beam 8 before passing through the firstlenslet array 10. The operation of the SLM unit will be described morespecifically further below with reference to FIGS. 3A-3B and 4A-4B.

[0054] Further provided in the device 1 is a magnification optics 22located in the optical path of light emerging from the SLM unit (or fromthe polarizer 18 as in the present example) and propagating towards aprojecting (or screen) surface 26. Thus, the beam 16 passes through thepolarizer 18 that produces a polarized intensity modulated beam 20indicative of an image to be projected by the magnifying optics 22 ontothe screen surface 26. As known to those skilled in the art, a projectedimage 28 will stay in focus for a large variety of distances between theprojecting device 1 and the screen surface 26 due to the nature of thelight source and its coherence in the given optical path. Alternatively,when light is not coherent the focus can be manually adjusted by movingthe magnifying lens 22 along the optical path.

[0055]FIG. 2 more specifically illustrates the operation of thediffracting element 34 (top-hat) used in the device of FIG. 1. Thetop-hat element by itself does not form part of the present inventionand its construction and operation are generally known, and consists ofthe following. A light source 30 that can be a laser diode or any othersource creates a light beam 32 in which the light intensity near theaxis of the beam is higher than that within the periphery of the beam(Gaussian intensity distribution). This beam is to be used for imaging(for example by the device 1 of FIG. 1) that requires substantiallyuniform light intensity distribution throughout the format of the image(i.e., within the cross section of the light beam). The diffractiveoptical element 34 is thus used to modify the beam intensitydistribution to produce a beam 38 of the substantially uniform intensitydistribution that can provide substantially uniform illumination of ascreen 36.

[0056] It should, however, be noted that the light beam arriving at theprojecting surface can still be somewhat non-uniform due to thelimitations of the top-hat component 34 (about 96% of transmittanceefficiency) and/or because of the non-uniform transmittance of the othercomponents in the optical path. Compensation for such non-uniformity canbe performed digitally by adjusting a control signal to every pixel ofthe pixel arrangement and providing an image-wise compensation bias, aswill be explained further below with reference to FIGS. 6 and 7A-7B.

[0057] Reference is now made to FIGS. 3A-3B and 4A-4B. FIG. 3Aillustrates the front view of the windowed structure of the SLM unit 12used in the device of FIG. 1, and FIG. 3B illustrates the structure ofthe lenslet array 10 used with the SLM of FIG. 3A. FIGS. 4A and 4B showthe beam propagation schemes through, respectively, the SLM of FIG. 3Aand the SLM-with-lenslet arrays of FIG. 3B.

[0058] Thus, as shown in FIG. 3A, the pixel arrangement (windowedstructure) 40 of a typical SLM is a two-dimensional array ofspaced-apart cells 42. Approximately 40% (varies from one SLM toanother) of the total surface of the structure 40 is composed of theactive cells 42 while the rest of the surface is composed of a frame 44that serves for mechanical support and control signals of the pixelarray. FIG. 4A shows the side view of the pixel arrangement 40 and thepropagation of a parallel light beam 50 therethrough. As can be seen, aportion of the incoming light 50 is blocked by the frame partitions 44,and only the remaining portion of the light 50 gets through the activecells 42. Thus the fill factor (i.e., effective transmission) for thistypical SLM structure is approximately 40%.

[0059]FIG. 3B illustrates the structure of a lenslet array 46 to be usedat opposite sides of the pixel arrangement 40 in the SLM unit accordingto the invention in order to increase the fill factor of the SLM. Thelenslet array 46 is a two-dimensional array of miniature lenses 48 thatmatches the pixel arrangement 40 of active cells 42. Each lens 48 mayhave a square-like shape, and the adjacent lenses are tangent to eachother thus fills most of the surface defined by the lens array 46 (i.e.,fill factor of approximately 100%).

[0060] As illustrated in FIG. 4B, showing the pixel arrangement 40 withthe first lenslet array 46 and the second lenslet array 46′, the firstlenslet array 46 is disposed at the input side of the pixel arrangement40 very close thereto (up to a physical contact) and the second lensletarray 46′ is disposed at the output side of the pixel arrangement 40also very close thereto, up to a physical contact. Practically, thefirst and second lenslet arrays can be integrated with the pixelarrangement 40 being mounted onto the opposite surfaces thereof. Eachlens 48 from the first array 46 and the respective opposite lens 48′from the second array 46′ are associated with the corresponding one ofthe active cells 42. Each of the lenses 46 is optically designed tofocus the corresponding component of the beam 50 onto a small areaaround its axis, at a distance of few microns behind the array. Thepitch of the lenses 46 is matched to the pitch of the active cells 42,so that there is one active cell 42 centered right behind each lens, andthe central point of the cell 42 is located in the back and front focalpoints of the respective lenslets 48 and 48′, respectively. The firstlenslet array 46 thus clusters the light beam 50 to correspond to thearea of the arrangement 40 (active surface of the SLM unit) by splittingthe light beam 50 impinging thereon into a plurality of components 64and focusing each component by the respective lenslet to the respectivepixel. The second lenslet array 46′ is substantially identical to thefirst lenslet array and is positioned opposite to the array 46 at theother side of the pixel arrangement 40. The second lenslet array mirrorsthe optical effect of the first array, thus causing a reverse opticaloperation on the beamlets 66 emerging from the active cells 42. Thesecond array 46′ diverge the individual beamlets 66 spatially modulatedby the arrangement 40 to create a light beam 80. The opticalcharacteristics of the lenslets in the arrays as well as the distancebetween the first and second arrays 46 and 46′ and the pixel arrangement40 can be determined by simple optical alignment methods known in theart so as to provide that the diameter of the beamlet 64 when reachingthe active cell 42 is smaller than the aperture of the cell 42, thus allthe light of the beamlet 64 passing through the active cell 42.

[0061] Thus, the total effect of the combination of the pixelarrangement 40 with the first and second lenslet arrays 46 and 46′ is asfollows: the incoming light beam 50 is divided by the passage throughthe lenslet array into separate focused beamlets 64, that then passthrough the cells 42 of the pixel arrangement 40, where they aremodulated according to the control signal (indicative of the data to beimaged) to produce a plurality of focused beamlets 66 emerging from thepixel arrangement.

[0062] The beamlets 66 pass through the lenslets 48′ that createtherefrom the parallel beam 80 of spatially modulated light. As aresult, the fill factor of the combined arrangement (lenslet arrays andpixel arrangement) is substantially higher than that of the pixelarrangement 40 by itself, and the total efficiency of the modulationprocess is thus substantially improved. The provision of the lensletarrays improves the transmission efficiency of the SLM by up to 30% andmore. It should be understood that when using the SLM with all activepixels, the efficiency of the SLM unit can be improved by a factor of 2due to the use of the lenslet arrays at both sides thereof.

[0063] As exemplified in FIG. 4C, the SLM unit may be of a 100 μmthickness, wherein the pixel arrangement (e.g., LC unit) has a thicknessof 10 μm and each of the polymer spacings P₁ and P₂ has a thickness of45 μm. The SLM unit may be manufactured using stamping and hat embossingtechniques.

[0064] As indicated above, the device of the present inventionpreferably utilizes a polarized light source. FIGS. 5A and 5Bdemonstrate the principles of intensity losses caused by usingunpolarized and polarized light sources, respectively. FIG. 5A shows thebasic optical path suitable to be used in a projector (or display) andutilizing a typical non-polarized light source 74. Such an optical paththus comprises the light source 74, a first polarizer 81, an SLM 84 anda second polarizer 96. The non-polarized light source 74 creates a lightbeam that can be represented by two components 76 and 78 of the oppositelinear polarizations. Both components 76 and 78 impinge onto the firstpolarizer 81, and only one of them can pass therethrough while the otheris rejected away, depending on the orientation of the plane ofpolarization of the device 81. Thus, the energy of a polarized lightbeam 82 emerged from the polarizer 81 is half of the input energy of thenon-polarized light beam. The SLM 84 receives the polarized light beam82 and modulates it by an input signal 86 to affect the polarization ofcorresponding light components of the beam 82 according to the inputsignal 86. For the simplicity of demonstration, the SLM 84 isrepresented as an element consisting of two polarization areas 88 and90, i.e., two cells or pixels one of which 90 being currently operatedby the control signal 86 and the other 88 being not. Hence, a lightportion 92 that emerges from the area 88 has its original polarization,and a light portion 94 that emerges from the area 90 has itspolarization affected in accordance to the input signal 86, e.g., hasthe orthogonal polarization with respect to its original polarizationstate. Both light portions 92 and 94 impinge onto the second polarizer96 that transmits only light identical in polarization to thattransmitted by the first polarizer 81. Thus, only the light portion 92,the polarization of which was not effected by the SLM 84, can passthrough the polarizer 96, and the intensity of the output beam 98 ishalf of that emerging from the first polarizer, and practically aquarter of the light generated by the light source.

[0065]FIG. 5B shows the basic optical path for use in a projector (ordisplay) and utilizing a high-ratio polarized light source as proposedby the present invention. To facilitate understanding, the samereference numbers are used for identifying components that are common inthe examples of FIGS. 5A and 5B. Thus, the optical path of FIG. 5Bcomprises a high-ratio polarized light source 75, an SLM 84, and apolarizer 96 (the need for the first polarizer 81 of FIG. 5A betherefore eliminated here). Light 100 generated by the light source 75is linearly polarized. A light portion 92 that emerges from the SLM area88 not operated by a control signal has its original polarization, andthe polarization of a light portion 94 that emerges from the SLM area 90operated by the control signal 86 is changed, e.g., to the orthogonalpolarization. Both light portions 92 and 94 impinge onto the polarizer96 that transmits only light with the polarization state identical tothat produced by the light source. Thus, only the light portion 92, thepolarization of which was not effected by the SLM 84, can pass throughthe polarizer 96. Similar to the previous example of FIG. 5A, theintensity of the output beam 98 is half of that provided by both lightportions 92 and 94. However, this intensity of both light portions 92and 94, i.e., the intensity of light impinging onto the SLM 84 is thatgenerated by the light source, namely, is twice as much of the intensityof the SLM input light 82 in the example of FIG. 5A, due to the use ofthe polarized light source. Thus the optical efficiency of the opticalpath of FIG. 5B is higher by a factor of 2 than that of FIG. 5A.

[0066] Turning now to FIG. 6, illustrating an image projecting device 3according to another embodiment of the invention. The same referencenumbers are used for identifying the common components in devices 1(FIG. 1) and 3. The device 3 additionally comprises a control unit CU(typically a computer device), wherein, in this specific example, themodulation driver 11 is a part of the control unit. The control unit CUthus comprises the driver 11 and a processor utility 330, and isassociated with an image recorder 332 and an environment sensor 334. Thedriver 11, that generates control signals (modulation signals) to theSLM pixel arrangement, is operable by a signal indicative of the imageto be projected (“image signal”). The image signal is generated by anappropriate signaling utility (not shown here) that may and may not be apart of the control unit of the projector device, and may typically be apart of an external computer device (such as PC, phone device, PDA,etc.) where the data to be images is produced. In this specific exampleof FIG. 6, the image signal is supplied to the driver 11 through theprocessor utility 330, but it should be understood that the image signalcan be supplied directly to the driver 11. The image recorder 332 is animaging device such as a video camera, which is oriented and operable togenerate data indicative of the projected image 28. The environmentsensor may include one or more sensing units detecting the environmentcondition of the kind defining the required intensity and/or colormixture of the projecting light, e.g., the light intensity sensor (suchas a CCD RGB/Temperature single pixel sensor) capable of detecting theintensity of ambient light in the vicinity of the screen surface 26 andgenerating corresponding data.

[0067] The processor 330 includes inter alia a controller CL, and threeutility parts (suitable software and/or hardware) U₁, U₂ and U₃ forprocessing, respectively, the image signal coming from the controller,the data coming from the image recorder, and the data coming from thesensor device. The utility U₁ is preprogrammed to analyze the imagesignal in accordance with the SLM pixel arrangement so as to performdigital image jittering and attenuation (changing of gray levels) on thepixel arrangement (via the driver 11) in order to reduce effects ofspeckles in the projected image, as will be described more specificallyfurther below with reference to FIGS. 8A and 8B. The utility U₂ ispreprogrammed to analyze the data indicative of the projected image 28and apply a digital processing of the image signal to thereby compensatefor the non-uniformity of the light intensity (brightness) within theprojected image. This is described below with reference to FIGS. 7A-7B.The utility U₃ is preprogrammed to analyze the data indicative of theenvironment condition and modulate the laser source 2 accordingly toadjust either one of the intensity and color mixture, or both. Thus, theprovision of the control unit and associated sensor devices (e.g.,camera, RGB/Temperature sensor), as well as the digital processing ofthe image signal, improves the quality of the projected image and theenergy efficiency of the projecting device.

[0068]FIGS. 7A-7B exemplifies the operation of the projecting deviceequipped with the processor 330 to provide digital compensation of alight modulated image on the target (screen surface). FIG. 7A shows thelight modulated image 108 containing non-uniform areas, with overintensive spots of light 110. A digital mask 112 designed to decreasethe light intensity within the area 114 is applied to the lightmodulated image 108 resulting in a final output image of uniformbrightness intensity on a target 116. FIG. 7B illustrates a basiccalibration procedure of the digital mask. The processor 330 (controllerCL) receives a pattern-image signal (generated either externally by avideo generating device (PC, VCR, etc.) or internally in the controllerCL), and generates a control signal indicative of the pattern image(Step I). This pattern-image signal is transmitted from the processor tothe driver 11 (Step II) to operate the SLM pixel arrangement accordinglyto enable projection of images with the original non-uniformity inbrightness. The light dispersal of the projected images is projected onthe screen surface (26 in FIGS. 1 and 6). A digital camera (332 in FIG.6), or any other kind of optical recording device, scans the projectedimage (Step III). Digital output data of the camera 332 indicative ofthe recorded image is received by the utility (U₂ in FIG. 6), thatanalyzes this data and operates together with the controller CL tocompare the data indicative of the recorded image with the generatedimage (created in accordance with the original input signal), and if theimages are identical, the calibration result in the form of a finaldigital mask is generated. If the lack of similarity in the signals isdetermined, an updated image is generated accordingly to obtain thefinal digital mask (steps IV and V). The controller CL then saves thecalibration result (digital mask status) in the driver 11 in order toupdate the projecting device with the correct parameters of brightnesslevels (step VI). It should be understood that the utility U₂ may not bea part of the processor, but be a stand-alone image processing unitconnectable to the image recording device 332 and to the processor 330.

[0069]FIGS. 8A and 8B more specifically illustrate the operation of thedevice according to the invention aimed at eliminating the speckleeffect which appears in the projected screen. As shown in FIG. 8A, anoriginal projected image 240 appears as an image with granular nature,the so-called “speckle effect”. This effect is observed with highlycoherent illumination, when the screen surface is not totally smooth. Inorder to eliminate this problem, the original image 240 is jittered andthe gray level is also attenuated by a maximum displacement of one pixelas it appears in a shifted projected image 242. Every pixel is nowjittered and attenuated with such velocity that the human eye is unableto notice this effect. For example, an original pixel 244 is jittered toa new position 246, so that this motion causes the coherence of theillumination to be at least partially destroyed, and the speckles “washout” during the projecting process, thereby producing a clear(speckles-free) image 248. The main operational steps of this procedureare shown in FIG. 8B. The original image (i.e., the image to beprojected) is grabbed from the driver 11 of the SLM, or from thecontroller CL as the case may be, (step A), and is processed by theutility U₁ to resize this image to free active pixel space used forjittering purposes (step B), thus leaving more extra space in thecorners and panels of the SLM pixel arrangement. Data indicative of theso-produced resized image is transmitted to the driver 11 (step C),where the image is shifted accordingly in a plane along twoperpendicular axis by shifting one or more image pixel to be in thepixel areas that were defined as area not in use, and modulated toprovide changes in gray level (step D). By this, a circular movement ofthe image on the SLM surface is provided in a high frequencycirculation, ensuring that the circulation process remains unnoticeableto the observer and at the same time ensuring that the image on the SLMsurface moves along the two axes repeatedly, resulting in the reductionof the speckle phenomenon viewed to the observer. It should be notedthat such parameters as the frequency of circulation, number of shiftedpixels, and the step of movement along either one of the two axes orboth is controlled by the given algorithm for different outcome resultsin different given situations.

[0070]FIG. 9 is a flow diagram of the main operational steps of theprocessor 330 to meet the requirements of the environment by utilizingcolor-mixture modulation of light inputting on the SLM pixelarrangement. In the present example, the environment sensor is atemperature sensor (i.e., sensing the intensity of the ambient light).The processor utilizes the sensing data to enable optimization of thelight source total consumption by changing switching modulation of colormixture according to the surrounding light condition, thus receiving themost intensive image exposed to the human eye in the contrast of thesurrounding interfering light. This is implemented in the followingmanner:

[0071] The sensor absorbs room light temperature (in differentwavelengths) in the vicinity of the screen surface (step 1). Dataindicative of the absorbed light is received by the processor (utilityU₃ in FIG. 6) that compares between the optimal (default) requiredimage/temperature in optimal surroundings and the light temperaturesensed on the projected surface (step 2). If a lack of similarity isdetermined, the processor updates color mixture modulation of the lightsource (step 3) in contrast to the optimal condition, and then allowsfor projecting the images according to the new color modulation (step4).

[0072] Reference is now made to FIGS. 10A-10E schematically illustratingdifferent implementation examples of projection of color images suitableto be used in the device of the present invention. FIG. 10A shows aschematic block diagram of the device according to one example of thisconcept and FIG. 10B shows one possible implementation thereof. FIG. 10Cshows a schematic block diagram of the device according to anotherexample, and FIGS. 10D and 10E show two possible implementations of thisexample. In the example of FIGS. 10A-10B, the primary colors R, G and Bare modulated via three optical paths, respectively, each having itsassociated SLM, while in the example of FIGS. 10C-10E, the primarycolors, R, G and B are modulated via the same optical path andconsequently the same SLM by utilizing the time beam modulator.

[0073] As shown in FIG. 10A in a self-explanatory manner, R, G, and Blight components 250, 252 and 254 are generated by three laser sources,respectively, e.g., compact laser diodes with appropriate powers inorder to get a white source. Each light component is widened by itsassociated beam expander, generally at 256, and the widened RGB beams258, 260 and 262 are then projected through the SLMs 264, eachcontaining a spatially modulated signal according to the input picture.Then, the spatially modulated RGB beams 266, 268 and 270 are combined bya set of beam combiners (beam splitters) 272 into a white beam 274 thatpasses through an imaging lens 276, and the so-produced output beam 278is projected onto a screen surface 280, where the output image appears.This arrangement is generally known and by itself does not form part ofthe present invention, but can be utilized in the projecting device ofthe present invention as shown in FIGS. 1 and 6, and as further shown ina self-explanatory manner in FIG. 10B.

[0074] As shown in FIG. 10C, the RGB laser beams 290, 292 and 294 aretime modulated by a beam modulator 296 (prior to or after passagethrough a beam expander). Then, the time-modulated beam 298 is projectedthrough a single SLM 300. The spatially (and time) modulated beam 302then passes through an imaging lens 304, and the so-produced output beam306 is projected onto a screen surface 308, where the output imageappears. Similarly, this scheme is generally known and can be used inthe device of the present invention. As shown in FIGS. 10D and 10E inself-explanatory manner, a diffractive element can be utilized by threetop-hat elements in front of the RGB laser beams 290, 292 and 294,respectively, or utilizing a common top-hat element.

[0075] The projecting device of the present invention can be used invarious applications being connectable to and/or forming part of acomputer device, such as PC, phone device, PDA, etc. FIGS. 11A to 11Hschematically illustrate different applications of the projecting deviceaccording to the invention.

[0076] In the example of FIG. 11A, the micro-projector device 138 of thepresent invention is used with a bi-directional semi-transparent screen136 of a laptop 134, and enables content viewing of images on both sidesof the screen. In the present example, the device 138 is supported by aholder 140, and is connected to a corresponding utility of the laptop toreceive an imaging signal to create a projected image 142 onto thescreen 136 to be viewed by two observers 144 and 148 at opposite sidesof the screen at two angles of observation 146 and 150, respectively.

[0077]FIG. 11B shows how the device of the present invention can be usedwith the conventional laptop computer while eliminating the need for anLCD screen typically used in these computers. To facilitateunderstanding, the same reference numbers are used to identify commoncomponents in the examples of FIGS. 11A and 11B. As shown, the image isprojected with an angle of projection 142 onto an external screensurface 160 opposite to the user's eyes, i. e, to be viewed by the userwith the angle of observation 164. It should be understood, although notspecifically shown, that the projector device 138 can be oriented toproject the image onto the table's surface adjacent to the computer, oronto the inner/outer surface of the laptop cover. Thus, user 144 whileworking on a portable laptop computer may advantageously operate with alarger screen, or while operating on a computer with no display at all,can utilize the projector device of the present invention for imagingdata on an external surface. It should be understood that suchprojection of images on an external screen surface can be used with anycommunication device, e.g., a phone device.

[0078]FIG. 11C exemplifies the use of several micro-projectors of thepresent invention, generally at 190, operable together to obtain a largeprojected screen 192 (video wall) by combining several small screens194, each produced by the corresponding one of the micro-projectors. Alarge image 198 is captured by a video camera 196 and transferred to theprocessor (image analyzer) 200 which operates to compare data indicativeof the large image 198 and data indicative of small images 194, andproduces an output signal to the controllers 202, causing them toreproduce the signal in such way that will cause the projectors 190 topresent the images 194 in alignment as a whole and seamless. The sameconfiguration can be used to project images onto a concave seamlessdisplay of any desired shape. This is schematically illustrated in FIG.11D. The main holder 206 holds several projector devices 204, each on aseparated branch holder 208. Each projector 204 projects a small image212 onto a concaved surface 210 to be viewed by an observer 216 as alarge concaved seamless image formed by small images partiallyoverlapping each other 214.

[0079]FIG. 11E illustrates the use of the present invention to projectthe same image onto the opposite sides of a semi-transparent screen tobe viewed by two users, while enabling to image on each of the screensurfaces an image intended for private use by the respective user. Inthis application, at least two persons 250 and 252 communicate face toface with each other around a desk 254, for example for the purpose of abusiness discussion or for playing a computerized game. Typically, thereis a graphical image that accompanies this communication, and bothparties need to see it and to contribute to it. Each party would like tokeep their own inputs to the joint image in their own custody, forpurposes of information security and for easy control. In is example,the person 250 has a micro-projecting device 258 that is associated witha control device 256. The projecting device 258 is supported by aspatial adjustment device 260 to project an image onto a verticalsemi-transparent screen 268 located between the two persons andsupported by a base 270. The other person 252 uses a similar projectingdevice 264 held by a support 266 and associated with a control device262 to project an image onto the vertical screen 268. Two projectedbeams 272 and 273 impinge onto the opposite faces of the screen 268, andcreate two different but well registered images. One projector isadjusted to project a mirror image of the data to be imaged, so thatboth images match each other. Person 250 sees an image, formed by thereflection of the beam 272 superimposed on the translucent beam 273,with a light collection angle 274, while the other person sees thereflected image 273 superimposed on the translucent image 272 with alight collection angle 276. Both persons see the same effective image.Each person can modify graphical information on its own projector, tocreate visual effects such as relationships between a mine and a tank ina war game, a drawing of a building and a layout of water pipes, a mapof a city and the layout of a new proposed residential complex, an X-rayof an anatomic organ and a scheme of a planned operation, etc.Registration marks in identical locations at the margins of the imagesserve to manually register the two images for exact overlap.

[0080]FIGS. 11F and 11G illustrate two examples, respectively, of yetanother application of the present invention consisting of projectingstereo images (it can be a non-stereoscopic projection, yet retinalone). The use of the micro-projector based on a spatially coherent lightsource allows obtaining a directional projection of images which cannotbe obtained using the common incoherent projection devices. In theexample of FIG. 11F, a user 310 is looking with his bare eyes into anopening 320 of a stereoscopic projector 322. Two coherent projectors ofthe present invention using laser diodes as their light source 324 and326 are located inside the stereoscopic projector, each directed intothe user's eyes 312 and 314. The user, due to the human process ofinterpreting the images that both eyes see, conceives the two separatedimages 316 and 318 to be two projections of a three dimensional object.If the images produced by the two coherent projectors consist of astereoscopic image, the user will see a three dimensional scene. Thescene can be colored and can be dynamic. As shown, two projectors 324and 326 are connected via two data lines 328 and 330, and are connectedto a video input source (processor) 332 that synchronizes the two linesand their video data and determines which part of the data is to be sentto the respective one of the projectors in order to partially have someof the data shared between both of the projectors, but mainly toseparate the relevant data to the relevant projector within the unit.Two sources of video data 334 and 336 are two cameras standing andtaking shots from different angles of a single object 338 that is thenreproduced as a stereoscopic output image. It should be noted that thevideo sources can be of any kind, and the use of the cameras 334 and 336only demonstrates a given non-limited example.

[0081] Since the laser output is not projected onto a screen but to theuser, the use of high optical output power is unnecessary and theoptical power used is no more than the optical power which is constantlybeing used in retinal projection goggles by Microvision Ltd., gogglesthat are also known to be used in the U.S army.

[0082] The importance of using coherent light is associated with thepossibility of avoiding light dispersion without the need forcontrolling this effect, and the possibility of shifting the beam to adesired direction, while any other kind of light would be dispersed.

[0083]FIG. 11G shows an alternative implementation of the same concept,wherein a single projector is used. Here, in order to optimize the powerconsumption, a rotating mirror 352 is used to shift the beam angle andthereby produce the same effect as obtained with the two projectors ofFIG. 11F. This configuration saves the use of another projection unitand associated optics, and also saves footprint and weight of the entiresystem. The user is looking at the projecting device 350 while bothbeams 348 and 346 are directed to the user's eyes 342 and 344. Therotation of the beam between eye 342 and 344 is carried out by themirror 352 that continues to rotate in a high rate while the sync unit354 delivers the required data to each eye to create the 3D stereoscopiceffect to the user. Video data is delivered the same way as in theprevious example, but only one input video line 356 is connected to thesync unit that controls the input and the rotating mirror with adifferent control line 358.

[0084] The present invention can be used with wearable stereoscopic 3Dglasses to provide a high efficiency 3D projection of images. Thisconcept is schematically illustrated in FIG. 11H. In order to produce astereoscopic 3D image, it is typically required to have two projectionchannels operable to provide differences between the two images. In mostcommon systems, wearable glasses are used to maintain the requiredeffect. However, the glasses' lack of transmittance causes the degradingof a large portion of light returned to the observer's eye, resulting inthe reduction of brightness and a need for a more powerful projector.Using a DLP projector (Digital light processing projector, which is MEMStechnology based) in this specific application, results in a lowerefficiency and brightness to the eye of the user as compared to thatobtained with an LCD projector, even though that in general, theefficiency on the projected surface itself is higher that that obtainedwithout the 3D glasses. This is due to the fact that the glasses arepolarizer based, and since the light coming from an ordinary LCD systemis polarized, it passes through the glasses in a more efficient mannerwithout losing as much as if it had come with random polarization, [likefrom a micro-mirror modulator based projector (a DLP projector)], whenbeing reflected from the projected surface towards the observer glasses.

[0085] The technique of the present invention provides for improving thetotal efficiency more than the both known concepts (Ordinary LCD,DMD/DLP), by simple modification of the projector device of the presentinvention as exemplified in FIG. 1 or FIG. 6. The modification consistsof removing the polarizer in the output side of the SLM unit, therebyhaving no polarizer at all (considering the use of the polarized lightsource). Hence, the projection image on the screen surface will not bevisible to users who don't wear the glasses and will be shown as a spotof light on the surface. Users who wear the glasses and watch at theimage, will see very clearly the images since their glasses function asthe polarizer in the output side of the SLM. Consequently, a highbrightness, high efficiency image will be obtained on the observer's 3Dglasses.

[0086] It should be understood that all the functional elements of thedevice of the present invention as described above in its variousimplantations can be integrated into a single hybrid component that canbecome an integral part of a communication and computing device. Theinvention is suitable to be implemented with multiple light sources inorder to produce full color, or by the use of a white light source. Thelight source can be of any kind, for example a laser diode.

[0087] Those skilled in the art will readily appreciate that variousmodifications and changes can be applied to the embodiments of theinvention as hereinbefore exemplified without departing from its scopedefined in and by the appended claims.

1-38. Cancel.
 39. An image projecting device (1) comprising a spatiallight modulating (SLM) pixel arrangement (5) defining an active surface;first and second lens' arrays (10, 14) at opposite sides of said SLMpixel arrangement (5), such that each lens in the first array and arespective opposite lens in the second array are associated with acorresponding one of the pixels; a light source system (LSS) operable toproduce an incident light beam of a predetermined cross sectioncorresponding to the size of said active surface; and a magnificationoptics (22) accommodated at the output side of the SLM pixelarrangement; the device being characterized in that: said first andsecond lens' arrays are integral with said SLM pixel arrangement beinglocated at opposite surfaces of the SLM pixel arrangement, and formingtogether with the SLM pixel arrangement a common SLM unit (12), each ofsaid first and second lens' arrays being spaced from the respectivesurface of the pixel arrangement a predetermined small distance up to aphysical contact, said first and second lens' arrays are implemented inpolymer spacers (P1, P2), respectively, at opposite surfaces of said SLMpixel arrangement.
 40. The device according to claim 39, wherein the SLMpixel arrangement has a pixel pitch substantially not exceeding 50 μm.41. The device according to claim 39, wherein the distance between thelens array and the respective surface of the SLM pixel arrangementsubstantially does not exceed 50 μm.
 42. The device according to claim39, wherein the SLM pixel arrangement comprises light modulatingmaterial defining said active surface.
 43. The device according to claim39, wherein the incident light impinging on to the SLM unit isspecifically polarized, the device comprising a polarizer unitaccommodated at the output side of the SLM pixel arrangement and havinga preferred orientation of a plane of polarization so as to be eithersubstantially the same as of the incident light beam or a 90-degreerotated with respect to that of the incident light beam.
 44. The deviceaccording to claim 43, wherein the light source system includes ahigh-ratio polarized light source for generating the polarized incidentlight.
 45. The device according to claim 43, comprising an inputpolarizer at the input side of the SLM pixel arrangement.
 46. The deviceaccording to claim 39, wherein the light source system comprises anoptical arrangement operable to provide substantially uniform intensitydistribution within the cross-section of the incident light beam. 47.The device according to claim 46, wherein said optical arrangementincludes a diffractive element operable to modify the beam intensitydistribution to produce the substantially uniform intensity distributionof the beam within its cross-section.
 48. The device according to claim39 wherein the light source system includes a beam expander affectingthe cross section of a light beam generated by the light source toprovide the cross section of the beam substantially of the size of theactive surface of the SLM unit.
 49. The device according to claim 39,wherein the light source system includes a light source generating alight beam of the cross section substantially of the size of the activesurface of the SLM unit.
 50. The device according to claim 39,comprising an image processor system operable to carry out at least oneof the following: (i) applying digital processing to data indicative ofan image to be projected so as to avoid or at least significantly reducethe speckles associated effects in the projected image; (ii) processingdata indicative of the projected image to correct for non-uniformitiesin the light intensity; and (iii) analyzing data indicative of theenvironmental condition to adjust at least one of the intensity andcolor mixture of the incident light beam.
 51. The device according toclaim 50, comprising an image recorder operable to generate the dataindicative of the projected image and transmit said data to the imageprocessor system.
 52. The device according to claim 50, comprising anenvironment sensor operable to generate the data indicative of theenvironment condition and transmit said data to the image processorsystem.
 53. The device according to claim 39, comprising a modulationdriver responsive to an imaging signal representative of an image to beprojected, to generate modulation signals to the SLM pixel arrangement.54. The device according to claim 53, wherein said modulation driver isconnectable to the image processor system to receive therefrom saidimaging signal.
 55. The device according to claim 39, comprising a timemodulator associated with said SLM pixel arrangement and operable toapply time modulation to different light components of the light sourcesystem.
 56. The device according to claim 55, wherein said differentlight components are different color components.
 57. The deviceaccording to claim 56, wherein said different color components areformed by a combination of highly polarized and non-polarized light. 58.The device according to claim 57, wherein the light source systemincludes at least one laser source for generating polarized light, andat least one light emitting diode for generating non-polarized light.59. The device according to claim 39, wherein the light source systemgenerates spatially separated different-color light components, thedevice comprising additional SLM pixel arrangements, each arrangementbeing associated with the corresponding one of the color lightcomponents.
 60. The device according to claim 39, comprising a rotatingmirror accommodated in front of a projecting surface, the device therebyenabling creation of a stereoscopic image.
 61. The device according toclaim 43, wherein said polarizer unit is constituted by the surface ofwearable glasses capable of imitating a three-dimensional image.
 62. Aprojecting system comprising at least two projecting devices, eachconstructed according to claim
 39. 63. The system according to claim 62,comprising a control unit connectable to each of the projecting devicesand operable to enable creation of a large combined image on aprojecting surface formed by images created by the projecting devices.64. The system according to claim 63, wherein said projecting surface isconcave.
 65. A computer system operable to generate data to be imaged,the system comprising the device according to any one of precedingclaims, wherein said device is connected to the data generating utilityof the computer system and operates to project the image onto at leastone external projecting surface.
 66. The device according to claim 40,wherein the distance between the lens array and the respective surfaceof the SLM pixel arrangement substantially does not exceed 50 μm.
 67. Amethod for projecting an image comprising: (i) providing a spatial lightmodulator (SLM) unit (12) composed of an SLM pixel arrangement (5)defining an active surface, and first and second lens' arrays (10, 14)at opposite sides of the SLM pixel arrangement, each of said first andsecond lens' arrays being spaced from the respective surface of said SLMpixel arrangement a predetermined small distance up to a physicalcontact with said surface, said lens' arrays being implemented inpolymer spacers (P1 , P2), respectively, at the opposite surfaces of theSLM pixel arrangement, each lens in the first array and a respectiveopposite lens in the second array are associated with a correspondingone of the pixels; and (ii) creating an incident light beam having apredetermined cross section corresponding to a size of said activesurface defined by the SLM pixel arrangement; (iii) passing said lightthrough the SLM unit and concurrently operating the SLM pixelarrangement with an imaging signal representative of an image to beprojected to thereby produce modulated light; (iv) passing the modulatedlight emerging from the SLM unit through a magnifying optics (22) to beprojected onto a projecting surface.
 68. The method according to claim67, wherein the SLM pixel arrangement has a pixel pitch substantiallynot exceeding 50 μm.
 69. The method according to claim 67 surface of theSLM pixel arrangement substantially does not exceed 50 μm.
 70. Themethod according to claim 67, comprising providing specific polarizationof the incident light beam propagating towards the SLM pixelarrangement, and passing the modulated light, propagating towards theprojecting surface, through a polarizer having a preferred orientationof a plane of polarization either substantially the same as that of theincident light beam or a 90-degree rotated with respect to that of theincident light beam.
 71. The method according to claim 70, comprisingpassing the randomly polarized light beam generated by a light sourcethrough a polarizer accommodated at the input side of the SLM pixelarrangement.
 72. The method according to claim 70, wherein the incidentlight beam is created by a high-ratio polarization light source.
 73. Themethod according to claim 67, wherein the incident light beam is createdby a light source emitting a light beam with a cross sectionsubstantially of the size of the active surface of the SLM pixelarrangement.
 74. The method according to claim 67, wherein the creationof incident light beam comprises passage of a light beam emitted by alight source through a beam shaping optics to thereby produce theincident light beam of the predetermined cross section.
 75. The methodaccording to claim 67, comprising processing said imaging signal priorto operating thereby the SLM pixel arrangement, to apply digitaljittering and gray level processing of pixels, thereby enablingreduction of speckles' effects in the projected image.
 76. The methodaccording to claim 67, comprising obtaining data indicative of theprojected image, analyzing said data and processing said imaging signalprior to operating thereby the SLM pixel arrangement, to thereby providesubstantially uniform intensity within the projected image.
 77. Themethod according to claim 67, comprising obtaining data indicative of anenvironment condition, analyzing said data, and processing said imagingsignal prior to operating thereby the SLM pixel arrangement, to therebyadjust at least one of the intensity and color mixture of the modulatedlight forming the projected image.
 78. The method according to claim 68,wherein the distance between the lens array and the respective surfaceof the SLM pixel arrangement substantially does not exceed 50 μm. 79.The method according to claim 68, comprising providing specificpolarization of the incident light beam propagating towards the SLMpixel arrangement, and passing the modulated light, propagating towardsthe projecting surface, through a polarizer having a preferredorientation of a plane of polarization either substantially the same asthat of the incident light beam or a 90-degree rotated with respect tothat of the incident light beam.
 80. The method according to claim 79,comprising passing the randomly polarized light beam generated by alight source through a polarizer accommodated at the input side of theSLM pixel arrangement.
 81. The method according to claim 79, wherein theincident light beam is created by a high-ratio polarization lightsource.